Relocatable X-ray imaging system and method for inspecting commercial vehicles and cargo containers

ABSTRACT

The present specification discloses a readily relocatable X-ray imaging system for inspecting the contents of vehicles and containers, and a method for using the same. The system is relatively small in size, and is used for inspecting commercial vehicles, cargo containers, and other large objects. The X-ray imaging system has a substantially arch-shaped collapsible frame with an X-ray source and detectors disposed thereon. The frame is preferably collapsible via a plurality of hinges and may be deployed into an X-ray imaging position, and collapsed into a transport position.

CROSS REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 12/822,183, filed on Jun. 24, 2010 which issued as U.S. Pat.No. 7,991,113, which is a continuation of U.S. patent application Ser.No. 12/339,481, filed on Dec. 19, 2008 which issued as U.S. Pat. No.7,769,133, which is a continuation of U.S. patent application Ser. No.11/198,919, which was filed on Aug. 5, 2005 and issued as U.S. Pat. No.7,483,510, which is a continuation of U.S. patent application Ser. No.10/600,629, which was filed on Jun. 20, 2003 and issued as U.S. Pat. No.6,928,141.

FIELD OF THE INVENTION

The field of the invention generally relates to X-ray inspection systemsused for security purposes. More particularly, the invention relates toa system and method for inspecting large objects such as commercialvehicles and cargo containers.

BACKGROUND OF THE INVENTION

X-ray inspection systems have generally been used to inspect thecontents of automobiles, trucks, rail cars, cargo containers, and othervessels of transport. Such systems are generally set up at airports,seaports, building entrances, border crossings, and other places wherecontraband; weapons, explosives, drugs, or other illegal items arelikely to be found in transit. X-ray inspection systems are also oftenused to verify the contents of containers and vehicles, and to ensurethe accuracy of shipping manifests and the like.

X-ray inspection systems for inspecting large objects are generally ofthe “fixed-site” variety, wherein vehicles or containers are brought tothe inspection site to undergo X-ray imaging. Such systems commonlycomprise a large inspection tunnel through which vehicles or containersare transported. The vehicles or containers are generally towed throughthe inspection tunnel, or are transported through the tunnel along alarge conveyor mechanism.

As a vehicle or container is transported through the inspection tunnel,an X-ray imaging source generates an X-ray beam toward the vehicle orcontainer. After the X-ray beam passes through, or penetrates, thevehicle or container, a detector receives the beam and produces anoutput signal representative of the vehicle or container, and of thecontents located therein.

In many of these fixed site systems, a plurality of signalsrepresentative of individual segments, i.e., successive cross sectionsor “slices,” of the vehicle or container may be transmitted, then summedtogether, to represent the entire vehicle or container. The outputsignal, or signals, is then converted into a visual image of the vehicleor container, and of the contents located. therein, which is sent to amonitor or viewing screen so that the image may be viewed by aninspection system operator. The system operator may then determinewhether any improper items are located, inside the vehicle or container,and whether the vehicle or container should be detained for physicalinspection.

While fixed-site X-ray inspection systems have adequately performed intheir particular implementations, the need has arisen for an X-rayimaging system that is readily relocatable and/or transportable to meetthe needs of a given site or event. This is especially true given thethreat that terrorism presents throughout the world, which has led to agreater need to inspect vehicles, containers, and other objects that maybe carrying contraband, explosives, or other dangerous or illegal items,in a variety of settings and venues.

Current fixed-site X-ray inspection systems are not suited to meet thisneed, as they are unable to accommodate areas and events that are notlocated at, or do not take place near, the inspection sites themselves.Moreover, current fixed-site X-ray inspection systems are unable todeter a large percentage of smugglers who simply move to alternate portsof entry to avoid sites that utilize the fixed-site inspection systems.

In an attempt to resolve these problems, relocatable inspection systemshave been developed that can be assembled and used at a variety oflocations to inspect large commercial vehicles and cargo containers. Inuse, these systems may either be stationary, similar to the fixed-sitesystems described above, or they may move relative to the vehicle orcontainer to be imaged while the vehicle or container remainsstationary. In the case of moving inspection systems, existing systemsare generally very large and are commonly powered by internal combustionengines. These moving systems may also include linear optical encodersto measure deflection and to compensate for image distortion that occurswhile the large system moves over the object to be imaged.

While existing relocatable X-ray inspection systems have been somewhateffective at inspecting vehicles and containers at multiple locations,they have many shortcomings. Specifically, they are generally extremelycumbersome to transport from one location to the next, and they requirelengthy disassembling and assembling procedures. Furthermore, thesesystems generally require powerful machinery to load and unload theircomponents onto and off of multiple transport trucks for relocation.Thus, significant time and expense are required to transport andassemble existing relocatable X-ray imaging systems. As a result, for agiven site or event requiring such an inspection system, substantialnotice must be given to allow for the time and preparation required totransport and assemble the system. This, in turn, presents significantlogistical problems where an event requiring security inspections occurson short notice.

In light of the above, a need exists for an X-ray imaging system that isused to inspect large trucks and cargo containers, which is readilyrelocatable, and flexible in terms of on-the-spot reconfiguration, suchthat a wide variety of site requirements may be met in a short amount oftime, and at minimal expense.

SUMMARY OF THE INVENTION

The present invention is generally directed to a readily relocatableX-ray imaging system for inspecting the contents of vehicles andcontainers, and a method for deploying and using the same. In apreferred embodiment, the system is relatively small in size compared toexisting X-ray inspection systems, and is used for inspecting commercialvehicles, cargo containers, and other large objects.

In one aspect of the invention, a substantially collapsible frame havingan X-ray source and detectors disposed thereon is used for imagingcommercial vehicles and large containers. The frame is preferablycollapsible via a plurality of hinges and/or slides disposed thereon.

In another aspect of the invention, a method for deploying the framefrom a car-carrier type truck or trailer into an X-ray imaging positionis described. The truck or trailer preferably includes means fordeploying the frame into the imaging position, and for collapsing theframe into a transport position.

In another aspect of the invention, the collapsible X-ray frame remainsstationary during X-ray imaging while a vehicle or container is driventhrough or towed through an inspection area defined under the frame.

In another aspect of the invention, the collapsible X-ray frame movesrelative to a stationary vehicle or container during X-ray imaging. Theframe may be self-propelled, self-guided movable along various types ofterrain via tires, and/or guided along one or more rails or tracks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of the relocatable X-ray inspection systemof the current invention set up at an inspection site.

FIG. 1B is an opposite-side perspective view of the relocatable X-rayinspection system of FIG. 1A.

FIG. 2 is a front-sectional view of an X-ray inspection frame accordingto one embodiment of the current invention.

FIG. 3 is a front view of an X-ray inspection frame according to asecond embodiment of the current invention.

FIG. 4A is a front view of an X-ray inspection frame according to athird embodiment of the current invention.

FIG. 4B is a side view of the X-ray inspection frame of FIG. 4A.

FIG. 5 is a side view of the X-ray inspection frame of FIG. 2 engaging atrack.

FIG. 6 is a perspective view of the X-ray inspection frame of FIG. 2 ina collapsed position on the bed of a delivery vehicle.

FIG. 7 is an opposite-side perspective view of the X-ray inspectionframe of FIG. 6 being deployed from the delivery vehicle onto a track.

FIG. 8 is a perspective view of the X-ray inspection system of thecurrent invention with a delivery vehicle set up as an operator cabin atthe inspection site.

FIG. 9 is a schematic showing an X-ray inspection system using lightsensors to guide the movement of the frame of the system.

FIG. 10 is a schematic showing light sensors for use in the embodimentof FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments will now be described. with reference to thefigures. To facilitate description, any numeral identifying an elementin one figure generally represents the same element when used in anyother figure. The configurations shown in the figures are forillustrative purposes only, and are not intended to limit the scope ofthe invention.

A. Description of System Elements

FIGS. 1A and 1B are opposing-side perspective views of a relocatableX-ray inspection system 10. The inspection system 10 may be used forinspecting vehicles, containers, and other objects capable of concealingcontraband, weapons, and the like. The inspection system 10 ispreferably used for inspecting large commercial trucks and cargocontainers, at various sites and events such as border crossings andentrances to government buildings. For ease of description, X-rayimaging of a truck 11 will be described herein, but it is to beunderstood that the inspection system 10 may also be used to inspectother vehicles, as well as containers and other objects capable ofconcealing improper items.

FIGS. 1A and 1B show the inspection system 10 set up at an inspectionsite having an operator cabin 13, with a raisable gate 15 connectedthereto, positioned at an entrance and/or exit to the inspection system10. The operator cabin 13 preferably contains all of the controlsnecessary for a system operator to manage and oversee the X-rayinspection process. The cabin 13 preferably contains a monitor fordisplaying X-ray images of objects and materials contained within atruck 11 being inspected, controls for raising and lowering the gate 15,an intercom system for communicating with truck drivers, and othercontrols for operating the various elements of the X-ray inspectionsystem 10, as further described below.

The inspection system 10 includes a substantially arch-shaped frame 12,which is preferably made from rigid structural steel or any othersuitable sturdy material. The frame 12 may be configured as a series oftruss beams, or may have any other suitable support configuration. Theframe 12 is preferably configured such that it may withstand harsh windand weather conditions, which may arise during inspection of trucks,such that the frame 12 will not topple over, fall apart, or driftsignificantly during the inspection process.

As shown in FIGS. 1 and 2, the frame 12 preferably comprises a first legsection 14 and a second leg section 16. The first and second legsections 14, 16 may have feet, wheels, tires, and/or any other supportelements located at a base portion thereof for resting on the inspectionsite surface, which may be the ground, a road, a parking lot, or anyother substantially uniform surface, as further described below.

The first and second leg sections 14, 16 are preferably connected to oneanother by a support beam section 18. The first and second leg sections14, 16 are preferably pivotally connected to the support beam section18, by hinges 35 or any other suitable pivoting mechanism, such that theframe 12 may be collapsed, as further described below. Additionally, thesupport beam section 18 preferably comprises two segments that arepivotally connected to one another at a hinge 37, or other suitablepivoting mechanism, that is located substantially equidistant from thefirst and second leg sections 14, 16, such that the frame 12 may becollapsed for transport, as illustrated in FIG. 6 and further describedbelow.

The area underneath the support beam section 18 and between the firstand second leg sections 14, 16 generally represents an “inspection area”wherein trucks may undergo X-ray imaging. As illustrated in FIG. 2, theinspection area may have a width A 13 to 15 feet, and a height B. Forexample, and not by way of limitation, width A may be approximately 13to 15 feet, and height B may be approximately 14 to 16 feet. In thisexample, inspection system 10 may accommodate vehicles having a width ofup to approximately twelve feet, and a height of up to approximately 14feet

Still referring to FIG. 2, when the support beam section 18 is in asubstantially horizontal imaging position, the support beam section 18may have a height X and an overall height X′. For example, and not byway of limitation, height X may be approximately 1.5 to 2.5 feet andoverall height X′ may be approximately 15.5 to 18.5 feet. When the frame12 is in the imaging position, the first and second leg sections 14, 16are preferably substantially vertical, and each leg section preferablyhas a width Y and an overall width Y′. For example, and not by way oflimitation, width Y may be approximately 1.5 to 2.5 feet, such that theframe 12 has an overall width Y′ of approximately 16 to 20 feet.

At least one of the first and second leg sections 14, 16 preferablyincludes an X-ray source 20 disposed thereon for generating an X-raybeam toward a truck 11 as it passes through the inspection area. In FIG.2, the X-ray source 20 is shown disposed on the first leg section 14,but it is to be understood that the X-ray source 20 may be disposed oneither, or both, leg sections 14, 16. The X-ray source 20 preferablygenerates X-ray beams toward detectors 22 disposed on the second legsection 16 and the support beam section 18, such that an entire truckmay be imaged, as further described below.

The X-ray source 20 may be any suitable X-ray beam generator, such as aradioisotopic source, an X-ray tube, or an electron. beam accelerator.The X-ray source 20 preferably produces X-ray beams ranging from 300 keVto 10 MeV. Suitable radioisotope sources include Cesium 137 and Cobalt60. X-ray tubes with accelerating potentials up to 500 keV are generallyavailable. Electron beam accelerator sources such as linear acceleratorsare generally available with energies from approximately 1 MeV to 10 MeVand higher.

The X-ray source 20 preferably produces a curtain or fan of X-rays sothat the truck may be imaged one cross-section or “slice” at a time asit passes through the inspection area. The individual slices may then besummed together to produce an X-ray image of the entire vehicle and itscontents. An example of an X-ray inspection system utilizing afan-shaped X-ray beam is disclosed in U.S. Pat. No. 4,366,382 toKotowski, which is herein incorporated by reference.

A suitable collimator mechanism may preferably be used to narrow andlimit the projected beam into a fan of dimensional, beams necessary toilluminate detectors 22 in the system 10, as further described below.The collimator mechanism also preferably reduces scattered radiation byreducing the total amount of X-rays emitted during truck inspection. Asa result, a reduced amount of shielding is required to protect thesystem operator and the truck drivers and passengers.

In an alternative embodiment, the X-ray beam may be collimated to aflying spot, as opposed to a fan, that moves in a line across one ormore detectors (detector configurations are further described below).Such a configuration effectively creates a line camera, which producesimages of an object in sections that may be summed together to producean image of the entire object and its contents. The X-ray beam mayalternatively be a pencil-beam, a cone-shaped beam, or any other beamsuitable for X-ray imaging. Thus, the fan-shaped beam will be describedherein by way of example only.

The radiation produced by the inspection system 10 is preferablymaintained at a relatively minimal level compared to the radiationproduced by larger fixed-site tunnel systems. This is preferred becausethe open configuration of the inspection system 10 may allow somescattered radiation to reach a system operator and/or truck passengers,which could endanger their health if the radiation produced is at highconcentrations. To further alleviate the danger caused by scatteredradiation, radiation shields (not shown in the figures) may be disposedon the first and second leg sections 14, 16 to prevent radiation fromescaping the inspection area. As a result, scattered radiation in theinspection system 10 is substantially reduced.

As noted above, detector arrays 22 are preferably disposed on or withinthe second leg section 16 and the support beam section 18 of the frame12 for detecting X-ray beams beam after they pass through, or penetrate,a truck 11 or other object being inspected. By placing detectors 22 onboth the second leg section 16 and the support beam section 18, anentire truck 11 and its contents may be imaged by the inspection system10, as illustrated in FIGS. 1A and 1B.

Each detector array preferably comprises a linear array of detectors,such as photodiodes, which absorb the X-ray beams transmitted throughthe truck 11 being inspected, and convert the absorbed X-ray beams intoradiographic signals representative of the truck 11 and of materialscontained therein. Alternatively, area detectors, such as scintillatingstrips or other suitable detectors, may be used to detect the X-raybeams that pass through the truck 11, and to convert the beams intorepresentative radiographic signals.

The signals produced by the detectors may preferably be sent to asuitable image producing mechanism, such as a system processor, viacables, wires, or other suitable means. Alternatively, the imageproducing mechanism may receive the detector signals remotely, such thatno wires or cables are required. The image producing mechanismpreferably converts the detector signals into visual images of the truck11 and of materials contained therein, which may be viewed on a monitor(or other viewing mechanism) by the system operator.

In a preferred embodiment, the X-ray inspection system 10 is equippedwith dual energy imaging capabilities. Dual energy imaging is a processwherein X-ray beams are produced by an X-ray source at multipleradiation energy levels to identify and distinguish between differenttypes of matter. A first detector element is preferably positionedopposite the X-ray source to receive and respond predominantly to X-raybeams in the lower energy range, while the remaining X-ray beams, beinggenerally of higher energy, pass through the first detector element. Asecond detector element is preferably positioned to receive and respondto the higher energy radiation passing through the first detectorelement.

A filter element may be interposed between the detector elements toenhance discrimination in the energy response of the respective detectorelements. The different detector elements preferably produce separateand simultaneous signals representing patterns of relatively lower andhigher energy emergent from a vehicle. Digital data processing andconversion equipment may then use these signals to produce distinctivedigital information representative of each of the images inside thevehicle.

For example, color-encoded images may be produced wherein organic,inorganic, and metallic materials located inside a vehicle appear asdifferent colors on a video monitor, such that a system operator mayreadily distinguish these materials from one another. Thus, by utilizingdual energy imaging in the inspection system 10, the system operator maymore easily identify improper materials located inside the vehicle. Dualenergy imaging may be particularly effective in the inspection system 10due to the reduced amount of scattered radiation produced, which mayotherwise interfere with optimal dual energy imaging performance.

As an alternative, multiple radiation sources, such as two X-ray sourcesor isotope sources may be mounted to one of the leg sections. Referringto FIG. 2, the first source 20 may be positioned as shown on leg section14. In addition, a second radion source may be positioned on frame 12 atanother location, such as near the pivot point 35. In this embodiment, areduced detector array may be used. For example, and again referring toFIG. 2, only the detectors 22 on leg section 16 may be used. Thisembodiment may provide for the acquisition of time-interleaved images.

The base portion of each of the first and second leg sections 14, 16 maybe equipped with feet, wheels, and/or tires, or any other elementsuitable for providing support and/or motion to the frame 12. The typeof element attached to the base portion of each leg section 14, 16preferably facilitates the method of X-ray inspection being implementedat a given site or event

When an imaging method is employed in which the frame 12 remainsstationary during X-ray inspection of a moving object, feet 24 arepreferably provided at the base portion of each of the first and secondleg sections 14, 16, as illustrated in FIG. 3. The feet 24 providesupport to the frame 12, and preferably substantially prevent the frame12 from sliding or moving along the inspection site surface during X-rayinspection. The feet 24 may be circular, or any other suitable shape,and are preferably made of rubber or any other material thatsubstantially prevents sliding motion of the frame 12 along the sitesurface. The feet 24 are preferably detachably connected to the frame 12via bolts, screws, or any other suitable fastening means. Alternatively,an upper portion of each of the feet 24 may be provided with threads,such that the feet 24 may be screwed into corresponding threadedopenings in the first and second leg sections 14, 16.

FIGS. 4A and 4B illustrated preferred embodiment of the frame 12 whereinthe frame 12 may move relative to the object being inspected. One ormore wheels 26, which preferably have tires 28 disposed thereon may berotatably connected to the base portion of each of the first and secondleg sections 14, 16. Each leg section preferably has two or more wheels26 connected thereto to provide balance and symmetry to the frame 12.The wheels 26 are further preferably pivotally attached to the first andsecond leg sections 14, 16 such that the wheels may pivot to steer theframe 12 during imaging of a stationary object, as further describedbelow.

The tires 28 are preferably made of rubber, or any other suitablematerial that provides substantially uniform rolling movement to theframe 12 along the site surface. In an alternative embodiment,caterpillar style tracks may be disposed at the base portions of thefirst and second leg sections 14, 16 to provide rolling movement to theframe 12. Caterpillar style tracks may be particularly effective whenthe frame 12 performs X-ray inspection on rough or uneven surfaces.

A laser guidance system, or other suitable guidance mechanism, maypreferably be used to direct the frame 12 during imaging of an object,as further described below. The laser guidance system may preferablyinclude a suitable laser beam emitter that may be placed on the ground,or at any other suitable location at the inspection site. A target maypreferably be positioned at a location where a system operator may aimthe laser beam to ensure that the beam is properly aligned, such thatthe frame 12 may travel toward and away from the beam along a dimensionof an object to be imaged, as further described below. The laserguidance system may also include one or more reflectors, which may bepositioned to reflect the laser beam toward the frame 12.

The frame 12, in turn, preferably includes one or more sensors forrecognizing the laser beam and for producing an output signal indicativeof the frame's position or the direction in which the frame 12 istraveling at any given moment. A processor, which may be disposed withinthe frame 12, in the operator cabin 13, or at any other suitablelocation, preferably receives the output signal from the frame sensors.The processor may then determine adjustments that must be made to thesteering of the frame 12 to ensure that the frame 12 is properlydirected along a dimension of an object to be imaged, as furtherdescribed below.

FIG. 5 illustrates an alternative embodiment wherein the base portion ofthe second leg section 516 of the frame 512 is equipped with one or morewheels, such as v-wheels 530, which are configured to engage a rail or atrack 532. The first leg section 514 may also be equipped with v-wheelsfor engaging a second track, or may be equipped with one or moreconventional wheels 534 for rolling along the inspection site surface,as illustrated. The conventional wheels 534 may have tires disposedthereon, or may be made of a hard plastic, or other suitable material,for rolling along the inspection site surface.

The track 32 is preferably secured to the inspection site surface viawickets, stakes, pins, or any other suitable fastening means. The trackmay be delivered via the delivery vehicle 40, or may be delivered by aseparate vehicle and installed before the frame 12 arrives at the site.Alternatively, the track may be permanently fixed at the site and system10 may be deployed at that location.

The track 32 may preferably be made of aluminum, or any other materialsuitable for supporting the frame 12. The v-wheels 30, in turn, may alsobe made of aluminum, or any other material suitable for rolling alongthe track 32. During imaging of a truck 11, the frame 12 is preferablyguided along the track 32 such that the frame 12 passes over the truck11 to image the contents located therein, as further described below.

In the embodiments wherein the frame is equipped with wheels and/ortires, the frame 12 preferably includes a self-propelling drive disposedthereon for powering and providing motion to the frame 12. There,self-propelling drive may include one or more synchronous drives, suchas electric servo motors or any other suitable source for providingmotive power to the frame 12. Servo motors may be used due to thepreferred relatively small size of the frame 12, which does not requirethe power of a large combustion engine, such as those used on existingmovable inspection systems, to provide motion thereto.

The servo motors may preferably be activated remotely by controlslocated inside the operator cabin 13, and/or by controls located on theframe 12 itself. Alternatively, the servo motors may have wires orcables running to the controls in the operator cabin such that the frame12 may be controlled from within the operator cabin 13.

The servo motors preferably provide motion to the frame 12 in at leasttwo general directions, e.g., forward and backward along a dimension ofa truck to be imaged, as further described below. In the embodiment inwhich the frame 12 is guided along one or more tracks 32, the servomotors preferably provide motion to the frame 12 in two directions alongthe track(s) 32.

The inspection system 10 may further include one or more generators forproviding power to the various components of the inspection system 10.The generator(s) may be located in the operator cabin 13, or at anyother suitable location at the inspection site. The generator(s) arepreferably electrically connected to the various electrical componentsin the system 10, such as the imaging equipment and monitors, via wiresand/or cables. The servo motors may also be powered and/or recharged bythe generator(s).

The X-ray inspection system 10 may preferably be delivered to aninspection site by a delivery vehicle 40, such as a car-carrier styletruck or a platform style tow truck, as illustrated in FIGS. 6 and 7, orby a trailer or other suitable vehicle. The delivery vehicle preferablyincludes a raisable bed section 42 to which the frame 12 may be attachedduring transport from one location to another. The raisable bed section42 preferably has a length to accommodate the height of the frame 12.For example, and not by way of limitation, the length may be from 16 to20 feet.

The bed section 42 preferably includes a first extendable arm section 44that may be detachably connected to an upper portion of each of thefirst and second leg sections 14, 16, and a second extendable armsection 46 that may be detachably connected to a lower portion of eachof the first and second leg sections 14, 16. The first and secondextendable arm sections 44, 46 are preferably detachably connected tothe first and second leg sections 14, 16 via locking levers, or anyother suitable locking mechanisms, that may preferably be locked andunlocked manually, and/or via controls located on or inside the deliveryvehicle, or at another suitable location.

As illustrated in FIG. 8, the delivery vehicle 40 may also be used as anoperator cabin. In such an embodiment, the delivery vehicle 40preferably includes controls therein for operating the X-ray inspectionsystem 10, as further described below. In this embodiment, a raisablegate 48 may preferably be detachably connected to a bumper, or othersuitable location, on the delivery vehicle, which the system operatormay raise and lower via controls located inside the delivery vehicle 40.

In the embodiment wherein the frame 12 remains stationary during truckinspection, a tow vehicle, or other suitable towing mechanism, may beemployed for pulling trucks through the inspection area, as furtherdescribed below. The tow vehicle may preferably include a winchmechanism having one or more cables that may be attached to the frontaxle or wheels of the truck to be inspected. Each of the cablespreferably includes a clamp, or other suitable attaching means; at afree end thereof, which may be secured to a wheel or axle, or othersuitable attachment point on the truck, so that the winch mechanism maypull the truck through the inspection area. In an alternativeembodiment, the delivery vehicle 40 may have a towing mechanism locatedthereon for towing trucks through the inspection area.

B. Description of the Deployment and Relocation Processes

The X-ray inspection system 10 is preferably readily deployable andcollapsible, so as to reduce the time and effort involved in moving thesystem 10 from one inspection site to another. When the delivery vehicle40 arrives at an inspection site, and at all times during transport, theframe 12 is preferably secured to the bed section 42 of the deliveryvehicle 40 in a collapsed transport position, as illustrated in FIG. 6.In the transport position, the first and second leg sections 14, 16 andthe support beam section 18 are preferably collapsed against one anothervia hinges 35, 37, such that they are oriented substantially parallel toone another. As a result, the frame 12 occupies a substantially minimalamount of space on the bed section 42 of the delivery vehicle 40.

Additionally or alternatively, leg sections 14, 16 may comprisetelescoping elements that may be retracted for transport and extendedfor deployment. Also, the leg sections 14, 16 may collapse themselvesvia hinges positioned along their length. As such, the leg sections 14,16 themselves may be extended from their retracted and/or collapsedposition when frame 12 is being deployed.

To deploy the X-ray frame 12 from the delivery vehicle, the vehicledriver preferably activates the first and second arm sections 44, 46,via controls located inside the vehicle 40, such that the arm sections44, 46 move outwardly from the delivery vehicle 40 in two directions. Asthe arm sections 44, 46 extend outwardly, the first and second legsections 14, 16 of the frame 12, which are secured to the arm sections44, 46, move away from one another.

The arm sections 44, 46 continue to extend outwardly until the twosegments of the support beam section 18 pivot and lock into an imagingposition wherein they are substantially linear to one another, andsubstantially perpendicular to the first and second leg sections 14, 16.In the imaging position, the frame 12 is preferably substantiallyarch-shaped, as illustrated in FIGS. 2 and 7. The two segments of thesupport beam section 18 and the first and second leg sections 14, 16preferably lock into the imaging position via locking levers, or anyother suitable locking mechanisms.

After the frame 12 is extended into the imaging position, the vehicledriver preferably raises the bed section 42 of the vehicle 40, asillustrated in FIG. 7, via controls located on or inside the vehicle 40,such that the frame 12 moves into a substantially upright position. Inthe embodiment wherein the first and second leg sections 14, 16 includev-wheels 30 for engaging a rail or track 32, the vehicle driverpreferably aligns the bed section 42 of the vehicle 40 with the track 32such that the wheels 30 engage the track 32 as the frame 12 is raisedinto an upright position. In the other described embodiments, the frameis preferably raised until the base portions of the first and second legsections 14, 16, and/or any tires or feet attached thereto, come intocontact with the site surface.

Once the frame 12 is in a substantially upright position on the sitesurface, the vehicle driver preferably detaches the frame 12 from thevehicle 40 by unlocking the locking levers manually or via controlslocated on or inside the vehicle. The frame then comes to rest on thesite surface in an upright position. In the embodiment where thedelivery vehicle 40 is used as an operator cabin, the driver preferablydrives the vehicle to a location from where the system operator maymanage the inspection process, such as that illustrated in FIG. 8. Ifthe delivery vehicle 40 is not used as an operator cabin, the driver maydrive the vehicle 40 away from the inspection area so that it does notinterfere with the inspection process.

The delivery vehicle and/or the vehicle driver may further deploy anydesired site accessories, such as awnings, signs, turnstiles, radiationshields, the operator cabin 13, and/or any other suitable Items, fromthe delivery vehicle 40. To accomplish this objective, a control cablemechanism, or other suitable deployment mechanism, may be located on thedelivery vehicle for deploying the desired accessories, or theaccessories may be deployed manually. The deployment mechanism maypreferably be operated via controls located on the outside of, or insidethe cab of, the delivery vehicle 40. Hydraulic lifts may also beemployed for deploying the operator cabin 13. In an alternativeembodiment; the operator cabin 13, and any other site accessories, maybe delivered by a separate vehicle having a suitable deploymentmechanism and/or hydraulic lift(s) located thereon.

After the accessories are deployed, the system operator (who may be thedelivery vehicle driver) may arrange the accessories in a suitablemanner throughout the inspection site. Radiation shields, for example,may preferably be set up around the inspection area, and/or may beattached to the frame 12, via bolts, screws, hooks, or any othersuitable attachment means. Accessories that are too large and/or heavyto be moved manually, such as the operator cabin 13, are preferablydeployed directly from the delivery vehicle to their desired locations.

The operator may then connect any electrical cables and/or wires leadingfrom the monitoring equipment, which is preferably located inside theoperator cabin 13, to the detector arrays 22 on the X-ray frame 12. Thecables and/or wires are preferably used for transmitting signalsproduced by the detectors to an image processor, or other suitableimage-producing mechanism, which provides a visual image of the vehicleand of contents located therein on the monitoring equipment.Alternatively, the detector array may produce output signals that arepicked up remotely by the image processor, in which case no cables orwires are required.

When the inspection system 10 is no longer required at a given site, thecomponents of the inspection system 10, and its accessories, maypreferably be loaded onto the delivery vehicle(s) in substantially theopposite order in which they were deployed. The vehicle driver maypreferably back the delivery vehicle 40 up to the frame 12, and thenraise the bed section 42 into a substantially vertical position viacontrols located on or inside the vehicle 40. The locking levers on theextendable arm sections 44, 46 of the delivery vehicle 40 may then belocked onto the first and second leg sections 14, 16 of the frame,either manually or via controls located on or inside the deliveryvehicle 40.

Once the frame 12 is secured to the bed section 42 of the deliveryvehicle, the operator, which may or may not be the same individual asthe driver, preferably lowers the bed section 42 into a substantiallyhorizontal position, via controls located on or inside the deliveryvehicle 40. The driver may then unlock the locking mechanisms at or nearthe hinge points 35, 37 on the frame 12, such that the frame 12 may becollapsed into a transport position. The extendable arms 44, 46 may thenbe retracted via the controls located on or inside the vehicle, whichcauses the frame to fold up into the transport position. In thetransport position, as described above, the first and second legsections 14, 16 and the support beam section 18 are preferably collapsedagainst one another such that they are oriented substantially parallelto one another, as illustrated in FIG. 6.

After the frame 12 is secured to the bed section 42 of the deliveryvehicle 40 in the transport position, the control cable mechanism and/orhydraulic lift(s) may be used to load the various other site accessoriesonto the delivery vehicle 40, and/or onto one or more other vehicles.Alternatively, the accessories may be loaded onto the vehicle(s)manually by one or more vehicle drivers and/or system operators. Onceall of the system components are loaded onto the vehicle(s), thevehicle(s) may be driven to the next inspection site, or to a storagefacility where the inspection equipment may be stored.

C. Description of the Inspection Process

Once the inspection system 10 is deployed and assembled, truck,inspection may begin. To begin the inspection process, a truck is drivento the inspection site, where the truck driver preferably followsdirections pertaining to how he/she should proceed, which may be writtenon signs set up at the site, and/or given verbally by the systemoperator. An intercom system, similar to that used at a drive-throughrestaurant, may preferably be set up at the entrance to the inspectionsite to allow the system operator to communicate instructions, to thetruck driver, and to answer any questions posed by the driver.

A gate 15, as shown in FIG. 1, which the operator may raiseelectronically from inside the operator cabin 13, may be connected tothe operator cabin 13 at or near the entrance and/or exit to theinspection system 10. When the system 10 is ready to inspect a truck,i.e., when the previous truck has completed the inspection process, theoperator may raise the gate(s) 15 to allow the next truck to enter,and/or the inspected truck to exit, the inspection system 10. Thegate(s) 15 may then be lowered by the operator, or lowered automaticallyonce the truck clears the reach of the gate 15, to prevent additionaltrucks from entering the inspection system 10.

After the driver receives instructions from the operator and/or signsposted at the inspection site, the driver preferably drives the truck toa location near the frame 12, where the truck is preferably aligned withthe inspection area of the frame. The site surface may preferablyinclude markings, cones, or other suitable markers to identify the areato which the driver should drive the truck. The truck may then beinspected via any of the methods described below, or via any othersuitable inspection process.

When cargo containers are brought to the inspection site to beinspected, the containers are preferably unloaded from a deliveryvehicle and placed at or near the inspection area of the X-ray frame 12.The containers may be unloaded manually, by a suitable control cablemechanism, a hydraulic lift, or by any other suitable method. The X-rayframe 12 may then be used to image the containers, via any one of themethods Ascribed below, or via any other suitable inspection method. Forease of illustration, inspection of trucks will be described below, butit is to be understood that other vehicles, containers, and/or any otherobjects capable of concealing improper items may be inspected by theinspection system 10.

1. Method One—Stationary X-Ray Frame Imaging a Moving Object

In the embodiment illustrated in FIG. 3, the X-ray frame 12 remainsstationary while a truck moves through the inspection area of the frame12 to undergo X-ray inspection. The system operator and/or signs havingdirections written thereon preferably instruct the truck driver to drivethe truck to an area in front of the frame 12. As described above, thesite surface may preferably to include markings, cones, or othersuitable markers to identify the area to which the driver should drivethe truck. The truck may then be pulled through the inspection area by atowing mechanism, or other suitable pulling device, or may be driventhrough the inspection area by the driver, as further described below.

In the embodiment where the truck is pulled through the inspection area,the truck driver preferably drives the truck to the area indicated infront of the frame 12, then turns the truck off and exits the truck. Thedriver may then walk along the outside of the inspection system 10 tothe opposite side of the X-ray frame 12, and await delivery of the truckafter it undergoes the inspection process, in a manner similar to thatof a person having bags scanned at an airport.

To facilitate this process, the operator cabin 13 is preferably providedwith an intercom system that allows the operator to communicateinstructions to the driver regarding where and how the driver shouldproceed. Warning signs and the like may also preferably be posted at theinspection site informing the driver of where it is safe and unsafe tostand or sit during the inspection process. A seating area may also beprovided where drivers may sit during the inspection process.

The system operator and/or other site workers may then attach clamps, orother suitable attachment devices, from the towing mechanism to thefront axle, wheels, or other suitable location, on the truck. The winchmechanism may then be activated to tow the truck through the inspectionarea under the frame 12. The winch mechanism preferably turns at auniform velocity such that the trucks towed through the inspection areaat a substantially constant speed, thereby minimizing/eliminatingdistortion in the X-ray imaging process.

As the truck begins to pass through the inspection area, an X-ray beamis generated from the X-ray source 20. The X-ray beam may be activatedby the operator, or may be activated automatically when the truckreaches a predetermined location under the frame 12. The X-ray beam ispreferably generated as soon as the cab section of the truck enters theinspection area, such that the cab section as well as the trailersection may be imaged. Alternatively, the X-ray beam may be generatedafter the cab section passes through the inspection area, such that onlythe trailer section undergoes X-ray inspection. In such an embodiment,the operator and/or one or more site workers may preferably physicallyinspect the cab section to determine whether any improper items arepresent

In the embodiment where the driver drives the truck through theinspection area, the X-ray beam is preferably generated after the cabsection containing the driver has completely passed through theinspection area, thereby minimizing the radiation to which the driver isexposed. The driver is preferably instructed by the system operatorand/or signs posted at the inspection site to drive the vehicle throughthe inspection area at a substantially uniform velocity, such thatdistortion in the X-ray imaging process is minimized/eliminated. Signallights, similar to conventional traffic lights or lights used at carwashes, may be included on the frame 12, to notify the driver whenhe/she should proceed through the inspection area.

In this embodiment, it is preferred that a device equipped with radar,lidar, or other suitable optical distance measuring equipment, bedisposed on the X-ray frame 12 for measuring the actual instantaneousposition and/or location of the truck as it passes through theinspection area. Such a device allows the system 10 to adjust the X-rayand imaging parameters to accommodate for the potentially non-uniformmotion of the truck, and to produce an image with minimal distortion.

Additionally, the radiation levels produced in the embodiment where thedriver remains in the truck during the inspection process are preferablymaintained within the range of 0.05 micro-Sievert to 0.10 micro-Sievert.This is roughly equivalent to the radiation that a person would beexposed to if he/she were exposed to sunlight for approximately fiveminutes, and is within ANSI Standard N43.17 (NCRP Report 116), whichoutlines safe limits of radiation exposure for humans. Thus, the harmfuleffects of radiation produced in the system 10 are preferably extremelyminimal, if existent at all.

In each of the stationary-frame embodiments, as well as the moving-frameembodiments described below, the X-ray beam is preferably produced as acurtain or fan of X-rays, as described above, so that the truck isimaged one cross-section or slice at a time as it passes through theinspection area. A collimator mechanism, as described above, ispreferably used to narrow and limit the projected beam into a fan ofdimensional beams to illuminate the detectors 22 on the frame 12. Thecollimator mechanism also limits scattering of the X-ray beam off of thetruck onto the detectors, which may otherwise result in a reduction ofcontrast in the X-ray images produced.

After the fan of X-ray beams passes through the truck, the detectorsreceive the X-ray beams and produce output signals representative of theindividual slices of the truck and of the materials located therein. Theoutput signals are sent to an image processor, which sums the outputsignals together and converts them into a visual image of the truck andof the contents contained therein. The visual image of the truck and itscontents is then sent to a monitor, or other suitable viewing screen,for inspection by the operator.

The operator may then view the images on the monitor to determinewhether any improper items are contained within the truck. As explainedabove, dual energy imaging is preferably used to inspect the truck suchthat visual images of metallic materials, organic materials, andinorganic materials located inside the truck are readily distinguishablefrom one another on the monitor. For example, in a preferred dual energyimaging scheme, organic materials, which may be indicative ofcontraband, may appear as an orange color on the monitor. Metallicmaterials, conversely, may appear as a blue color. As a result, thesystem operator is preferably able to readily identify organic materialslocated inside the truck, which is made up of mainly metalliccomponents.

If the operator determines that one or more improper items might becontained within the truck, the operator may then exit the operator,cabin 13 to physically inspect the truck. Alternatively, one or moretruck inspectors may be employed to physically inspect trucks suspectedof containing improper items. After physically inspecting the truck, theoperator and/or inspectors may detain the driver and the truck if one ormore improper items are found inside the truck. If no such items arefound, the operator and/or inspectors may then inform the driver thathe/she is free to exit the inspection site, and the driver (and anypassengers) may then enter the truck and drive away from the inspectionsite.

Once the previously inspected truck exits the inspection system 10, theoperator may then raise the gate 15 on the operator cabin 13 to allow anew truck to enter the inspection system 10 to be inspected. Thedescribed inspection process may, then be repeated for the new truck.The entire inspection process is preferably performed in less than twominutes per truck (for trucks not suspected of containing any improperitems), more preferably in less than one minute. However, the time ofthe inspection may vary.

2. Method Two—X-Ray Frame Moving Along a Track to Image a StationaryObject

In the embodiment illustrated in FIGS. 1, 2, and 5, the X-ray frame 12may move on one or more tracks 32 or rails along a length of a truckwhile the truck remains stationary. As described above, the deliveryvehicle 40 preferably raises the frame 12 such that the v-wheels 32 onthe second leg section 16 engage the track(s) 32. The system operatormay then activate the servo motors, or other self-propelling drives, onthe frame 12 to move the frame into imaging position. In a preferredembodiment, the frame 12 may be positioned adjacent to the operatorcabin when the frame 12 is in the imaging position.

Once the frame 12 is in the imaging position, the system operator and/orsigns having directions written thereon preferably instruct the truckdriver to drive the truck to an area in front of the frame 12. In apreferred embodiment, the driver preferably drives the truck up to thegate 15 on the operator cabin 13, as illustrated in FIGS. 1A and 1B, andthen exits the truck so that the truck may be imaged. The driver maythen move to an area of the inspection site away from where the X-rayinspection occurs.

To facilitate this process, the operator cabin 13 is preferably providedwith an intercom system that allows the operator to communicateinstructions to the driver regarding where and how the driver shouldproceed. Warning signs and the like may also preferably be posted at theinspection site informing the driver of where it is safe and unsafe tostand or sit during the inspection process. A seating area may also beprovided where drivers may sit during the inspection process.

Once the driver is safely out of the imaging area, the system operatorpreferably activates the servo motor(s), or other self-propelling drive,to start the frame 12 in motion along the track 32, such that the frame12 begins to pass over the truck. Synchronous drives, such as servomotors, are preferably used so that the speed of the frame 12 may bemaintained at a substantially constant velocity as the frame 12 passesover the truck, thus reducing/eliminating image distortion that mayotherwise occur if the frame 12 velocity varies.

As the frame 12 passes over the truck, an X-ray beam is generated fromthe X-ray source 20. The X-ray beam may be activated by the operator, ormay be activated automatically when the frame 12 reaches a predeterminedlocation on the track 32. The X-ray beam is preferably generated as soonas the frame 12 reaches the cab section of the truck, such that the cabsection as well as the trailer section may be imaged. Alternatively, theX-ray beam may be generated after the frame 12 passes over the cabsection, such that only the trailer section undergoes X-ray inspection.In such an embodiment, the operator and/or one or more site workers maypreferably physically inspect the cab section to determine whether anyimproper items are present.

The X-ray beam is preferably produced as a curtain or fan of X-rays anddetected in the same manner as that described for the stationary-frameembodiments. Additionally, dual energy imaging is preferably used toinspect the truck such that visual images of metallic materials, organicmaterials, and inorganic materials located inside the truck are readilydistinguishable from one another on the monitor, as described above.

Once the frame 512 has passed over the entire length of the truck, theoperator preferably deactivates the X-ray source 20, or the X-ray source20 shuts off automatically when the frame 512 reaches a predeterminedlocation on the track 532. The operator may then view the images on themonitor to determine whether any improper items are contained within thetruck.

If the operator determines that one or more improper items might becontained within the truck, the operator and/or the truck inspectors mayphysically inspect the truck, as described above. After physicallyinspecting the truck, the operator and/or inspectors may detain thedriver and the truck if one or more improper items are found inside thetruck. If no such items are found, the, operator then raise the gate 15on the operator cabin, and the driver (and any passengers) may thenenter the truck and drive away from the inspection site.

Once the previously inspected truck exits the inspection site, theoperator may activate the servo motors(s) or other synchronous drives onthe frame 512 to return the frame 512 along the track(s) 532 to theimaging position, and a new truck may then enter the inspection system10. The described inspection process may then be repeated for the newtruck. The entire inspection is preferably performed in less than twominutes per truck (for trucks not suspected of containing any improperitems), more preferably in less than one minute. However, the time ofthe inspection may vary.

Alternatively, the frame 512 need not be returned to its originalposition to perform another scan. This embodiment effectively providesbi-directional scanning or inspection. To this end, once the previouslyinspected truck exits the inspection area, another truck or othervehicle to be inspected may be positioned in the imaging area with itsdriver safely away therefrom. The system operator may then activate theservo motors, or other self-propelling driver, to start the frame 512 inmotion along track 532 in the opposite direction as the previousinspection. The vehicle may then be inspected in the manner discussedabove. This reduces throughput delay due to the frame 512 being returnedto a single starting position for each inspection. This also preferablyreduces the wear on the components of the system.

3. Method Three—Self-Guided X-Ray Frame, Moving Over a Stationary Objectto Image the Object

In the embodiment illustrated in FIGS. 4A and 4B, the frame 12preferably includes a plurality of wheels 26, which preferably, havetires 28 disposed thereon, disposed at a base portion of each of thefirst and second leg sections 14, 16, as described above. Once the frame12 is deployed from the delivery vehicle 40, as described above, theX-ray imaging process is performed in essentially the same manner asthat described above for the track-guided frame, with the exception thatthe frame is self-guided and may operate without a track.

In this embodiment, the frame 12 is preferably guided by a suitableguidance mechanism such as an RF guidance system or laser guidancesystem, or other suitable guidance mechanism. The following discussionpertains to a preferred embodiment involving a laser guidance system.However, it should be noted that other types of guidance systems may beused and the following discussion is applicable to the use of such otherguidance systems.

In a preferred embodiment, the system operator or other site workerplaces or secures a suitable laser beam emitter to the site surface, orother suitable location, and aims the beam at a target positioned in thegeneral path of travel of the frame 12. The operator or site worker mayoptionally position one or more reflectors at predetermined locations atthe inspection site, which may be used to reflect the laser beam towardthe target and/or frame 12 during X-ray inspection.

Once a truck arrives at the inspection site, and the driver is safelyout of the imaging area, as described above, the system operatorpreferably activates the laser beam, or other guidance system, and servomotor(s), or other synchronous drives, on the frame 12. The sensors onthe frame detect the laser beam and the system processor instructs theframe to follow the laser.

The guidance system may preferably be programmed with tolerance limitswithin which the frame 12 preferably travels in order to achieve optimalimage quality. In this manner, the frame 12 need not travel in aperfectly straight line to produce a useable image, as long as itremains within the tolerance limits. The tolerance limits may vary, butfor example and not by way of limitation, the tolerance limits may beless than 6 inches from left to right and/or up and down, but may begreater or lesser depending on the sensitivity of the image-producingequipment. The frame 12 preferably accelerates, decelerates and travelsat a pre-determined speed that may be computer controlled or operatorcontrolled. The speed at which the frame 12 travels may vary accordingto the object being inspected or scanning equipment used in order topreferably provide usable X-ray images.

As the frame 12 passes over the truck, it is guided by the laser whichis “tracked” by the sensors on the frame. If the frame moves in anydirection up to the designated tolerance limit, the sensors inconjunction with the system processor instruct the frame 12 to moveslightly in the opposite or other corrective direction. For example, ifthe side-to-side tolerance limit is six inches, and the frame 12 movessix inches to the left during the inspection process, a sensor on theframe recognizes that the frame is “off course,” and the systemprocessor instructs the frame 1 to move slightly to the right as itprogresses over the truck. Furthermore, the speed at which the frame 12travels may be monitored and varied as desired.

To accomplish this objective, the wheels 26 are preferably pivotallyattached to the first and second leg sections 14, 16 such that thewheels may pivot to steer the frame 12 and keep the frame 12 within thetolerance limits of the guidance system. Also, the wheels, tracks orother mechanism used to guide the frame 12 may be independently driven.For example, one track, wheel or other mechanism attached to one frameleg may be temporarily slowed as compared to the other wheel, track orother mechanism attached to the other frame leg such that the frame maybe steered from side to side.

As indicated above, the self-guided embodiment of the present inventionas discussed above may be used with other guidance systems. For example,the frame 12 may alternatively be guided by a guide wire laid on theground in the direction of the intended travel path of the frame 12. Theguide wire may be secured to the ground by any suitable means such as bystakes or tape. The guidewire system may provide for various motionpaths beyond a forward/reverse direction of travel. In anotherembodiment, the frame 12 may follow a painted, or otherwise marked, linepositioned on the ground. Suitable sensor or detectors may be positionedon the frame 12 to gauge the frame's position relative to the line.

As a further alternative, the travel of frame 12 may be controlledoptically by a light. In this manner, the frame 12 may move toward thelight as its destination. Suitable optical sensors or detectors, e.g.,photosensors, mounted on the frame 12 may be used to detect the light. Asecond light may be used for the reverse direction. In other words, theframe 12 would travel in reverse towards the second light.

In this embodiment, the light source may be located at or near a pointtowards which the frame 12 is intended to move. The sensors may eachphotosensors positioned in proximity to each other. The light source maybe positioned such that the path of the light may be mid-way between thephotosensors. Telescopes or other mechanisms that may focus the lightimpinging on the photosensors may be used. As the frame 12 travels, itmay veer from a straight line or other desired path. As such, certainphotosensors in the sensor mounted to the frame 12 may be moreilluminated than other of the photosensors in the sensor. Informationreflecting the relative illumination of the photosensors may be sent toand processed by the processor described above to cause the frame 12 tochange its path of travel, e.g., to bring the frame 12 back to theoriginal straight line or other desired path.

This may occur by the processor sending signals to the drive mechanismson the legs 14, 16 of the frame 12 such that one of the legs is sped upor the other is slowed or a combination of both. As noted above, legs14, 16 may be equipped with independent driven wheels, tracks or othermechanisms. The variance between the illumination of the two sides'photocells may reflect how far off course the frame 12 is. As thevariance increases, thus indicating that the frame 12 is more offcourse, the speed difference between the legs 14, 16 may be increased.

This embodiment is now further described with reference to FIGS. 9 and10. FIG. 9 is schematic wherein the frame 12, having legs 14, 16, andhaving left wheels 26L and right wheels 26R, includes a guidance system.It should be noted that the frame 12 may embody configurations differentthan that shown in FIG. 9 or different from the frames 12 shown in theother figures discussed above. Accordingly, the guidance systemdiscussed below may be used with frames having various configurations.

Frame 12 may preferably move in the forward and reverse directions perthe guidance system. The guidance system may include sensors 72 and 74that may be mounted to opposite sides of the frame 12 via brackets 73.Other appropriate mounting locations and mounting hardware 73 may beused. While sensors 72, 74 are shown in FIG. 9 on the right side offrame 12, sensors 72, 74 may be mounted elsewhere on the frame, such ason the left side. The guidance system may also include light sources 76and 78. Light sources 76, 78 may emit a laser light or some other typeof light that may be detected by sensors 72, 74. Accordingly, thereference to “light” below is not intended to be limited to somespecific type of light.

Light source 76 may emit light generally along the path 80 towardssensor 72. Light source 76 is preferably positioned so that light path80 generally represents the desired path of forward travel of frame 12.Similarly, light source 78 may emit light generally along path 82towards sensor 74, and is preferably positioned so that light path 82generally represents the desired path of reverse travel of frame 12.Light sources 76, 78 may be mounted on a tripod or some other movablestructure (not shown) resting on the ground near the inspection sight.Alternatively, light sources 76, 78 may be mounted to an appropriatewall or other stationary structure. It is preferred that sensors 72, 74are positioned relative to each other so that the light emitted fromsources 76, 78 do not shine into each other.

Referring to FIG. 10, sensors 72, 74 are now further described. Thesensor in FIG. 10 bears the reference numeral 72, but sensor 74 may besimilarly configured. As shown, sensor 72 preferably includes lens 84and photosensors. 86 and 88. Lens 84 may comprise any suitable materialto accommodate, the type of light being used. While two photosensors 86,88 are shown, it should be noted that some other number of photosensors,or a photosensor array, may be used.

As mentioned above, light path 80 generally represents the desired pathof travel of frame 12. If the frame 12 has been moving along in arelatively straight line along light path 80, light path 80 preferablyimpinges on the lens 84 at or near its mid-point 84A. This is preferablyaccomplished by positioning light source 76 relative to the frame 12 andsensor 72 so that the direction of light path 80 does represent thedesired path of travel. So when the frame 12 is moving along path 80 andis oriented properly, the direction of the light beam is preferably notsignificantly altered as it passes through lens 84 and impinges onphotosensors 86, 88.

Accordingly, the amount of light received by each of photosensors 86 and88 from light beam 80 after it passes through lens 84 is preferably thesame, about the same, or within some range of tolerance. It should benoted that while light beam 80 is shown in FIG. 10 as a single line,light beam 80 will generally irradiate each of photosensors 86 and 88 tosome extent even though these photosensors may not be exactly in thepath of the light beam 80. In other words, when the frame 12 isgenerally on the correct path 80 and is oriented correctly, the lightbeam 80 covers equal, about equal, or similar enough portions of thephotosensors 86, 88.

Signals may be generated reflecting the amount of light energy receivedby each of the photosensors 86 and 88. These signals may be sent to aprocessor (not shown in FIG. 10 but described above) for processing.Where the respective signals from photosensors 86, 88 show that theamount of light that they respectively received is the same, about thesame, or within a specified tolerable range, the processor need notinstruct the drive wheels 26 to alter the path of the frame 12. As such,frame 12 may continue to generally travel in the direction of thedesired path 80.

If the frame 12 has strayed from the desired path 80, light beam 80 willimpinge on lens 84 at a location other than its mid-point. For example,if the frame has strayed to the left, beam path 80 will impinge on lens84 at a location 84B as shown in FIG. 10. In this situation, beam path80 actually impinges on lens 84 from a different path denoted as path80B. As such, the direction of beam path 80B will be altered as itpasses through lens 84 such that beam path 80B will more stronglyirradiate photosensor 88 than photosensor 86.

In this situation, the signals reflecting the amount of light receivedby photosensors 86, 88 will be sufficiently different. These signals maybe sent to a processor which may instruct the drive wheels 26 to alterthe direction of frame 12 to compensate. To this end, for example, theprocessor may instruct wheels 26L to speed up, wheels 26R to slow down,or a combination of the two. As the direction of travel of the frame 12is altered towards the desired path of travel 80, the light emitted fromsource 76 will eventually impinge on lens 84 at about its midpoint 84Aand both photosensors 86, 88 will be illuminated equally, about equally,or within some specified tolerance range. When this occurs, the signalssent to the processor will be the same, about the same or within somespecified tolerance range such that further compensation by the wheels26 may cease.

If the frame 12 has strayed to the right of the desired path 80, beampath 80 will impinge on lens 84 at a location 84C as shown in FIG. 10.In this situation, beam path 80 actually impinges on lens 84 from adifferent path denoted as path 80C. As such, the direction of beam path80C will be altered as it passes through lens 84 such that beam path 80Cwill more strongly irradiate photosensor 86 than photosensor 88.

In this situation, the signals reflecting the amount of light receivedby photosensors 86, 88 will again be sufficiently different. Thesesignals may be sent to a processor which may instruct the drive wheels26 to alter the direction of frame 12 to compensate. To this end, forexample, the processor may instruct wheels 26R to speed up, wheels 26Lto slow down, or a combination of the two. As the direction of travel ofthe frame 12 is altered towards the desired path of travel 80, the lightemitted from source 76 will eventually impinge on lens 84 at about itsmidpoint 84A, and both photosensors 86, 88 will be illuminated equally,about equally, or within some specified tolerance range. When thisoccurs, the signals sent to the processor will be the same, about thesame or within some specified tolerance range such that furthercompensation by the wheels 26 may cease.

The guidance of frame 12 in a reverse direction may occur in similarfashion. In other words, should the frame 12 proceed on the correct pathand be oriented correctly, the light beam 82 from source 78 will impingethe lens 84 at the midpoint and the frame 12 will be instructed tocontinue travelling on the same course. If the frame 12 strays from thedesired path 82, signals may be generated reflecting the differentamounts of light received by photosensors 86, 88 which may result in theprocessor providing appropriate compensating instructions to the wheels26.

The guidance system of this embodiment may also indicate when the frame12 has reached the end of the desired length of forward or reversetravel. To this end, the guidance system may include “end of travel”markers 90 and 92 that may be located at the ends of the desired forwardand reverse paths of travel. Markers 90, 92 may be positioned relativeto the frame 12 in similar fashion to light sources 76, 78. “End oftravel” sensors 94 and 96, which correspond to markers 90, 92respectively, are preferably mounted to frame 12 via brackets 97.

Sensors 94, 96 preferably detect the proper point for the frame 12 tostop. Sensors 94, 96 may be proximity sensors that detect an object,i.e., marker 90 or 92, such as a metal plate or a pole. In oneembodiment, the light sources 76, 78 may be mounted to markers 90, 92respectively. When sensors 94, 96 detect the end of the path of forwardor reverse travel, they may generate appropriate signals to a processorto instruct the wheels 26 to stop moving and/or move in the reversedirection.

In general, the guidance system described above may operate as follows.The vehicle to be inspected and/or frame 12 are positioned relative toeach other and relative to the light sources 76, 78 and markers 90, 92.As the inspection begins and the frame 12 moves forward, the lightsource 76 emits light which is received by sensor 72 for appropriatesignals to be generated and sent to the processor. Appropriateinstructions are then sent to the drive wheels 26. After the inspectionhas occurred and the frame 12 has reached the end of its desired forwardlength of travel, sensor 94 sends appropriate signals to the processorto stop the frame 12 and reverse its direction. The reverse movement offrame 12 may then be guided by light source 78 and sensor 74 up untilthe time that sensor 96 detects that the end of the desired reverse lineof travel has been reached. The frame 12 may then be stopped, theinspected vehicle may then exit the inspection area, and anotherinspection may occur.

The frame 12 is preferably maintained in a relatively stiffconfiguration such that frame deflection during X-ray inspection isreduced or eliminated, which in turn reduces or eliminates imagedistortion. To further maintain proper physical alignment, the frame 12may be equipped with strain gauges that measure strain and/or stressbuilding in the frame 12 before frame deflection actually occurs. Thestrain gauges may then act to counteract and reduce the strain and/orstress occurring in the frame 12 such that deflection of the frame doesnot occur.

The use of strain gauges provides an advantage over prior art mobileinspection systems, which generally use linear optical encoders andshaft encoders to measure and compensate for deflection after thedeflection has already occurred. Linear optical encoders and shaftencoders, or other suitable compensating equipment, may be used in theinspection system 10, however, if they are more suited to the imageproducing equipment being used.

The frame 12 may include proximity sensors or physical contact switchesto stop the frame 12 if it comes close to or in contact with anotherobject. Additionally, system 10 may be equipped with cutoff mechanism,e.g., “deadman” switch mechanism that may be used by the operator tostop the frame 12. The cutoff mechanism may also be activatedautomatically under computer control if certain conditions arise.

After the frame 12 passes over the complete length of the truck beinginspected, the X-ray source may be deactivated and the frame 12 may thenmove in the opposite direction over the truck such that the frame 12returns to its imaging position. The operator may then view the image ofthe truck and its contents on the monitor to determine whether anyimproper items might be present. The operator may then detain the truckand the driver if improper items appear to be present, or inform thedriver that he/she is free to leave the inspection site if no improperimages appear on the monitor, as described above. Once the previoustruck is cleared or detained, and moved away from the inspection area,the next truck may enter the inspection system 10 to undergo X-rayinspection.

Thus while embodiments and applications of the present invention havebeen shown and described, it would be apparent to one skilled in the artthat other modifications are possible without departing from theinventive concepts herein. The invention, therefore, is not to berestricted except in the spirit of the claims that follow.

What is claimed is:
 1. A relocatable security inspection system,comprising: an X-ray source; a vehicle having a bed section; and a framesecured to the bed section, wherein the frame comprises a first legsection, a second leg section, and a support beam, wherein the first legsection is connected to the support beam via a hinge and the second legsection is connected to the support beam via a hinge, and wherein, whenin a transportation position, each of the first leg section, the secondleg section, and the support beam are collapsed against one another in asubstantially parallel orientation.
 2. The relocatable securityinspection system of claim 1, further comprising a detector adapted tobe disposed on the frame and configured to produce an output signalrepresentative of a scanned object.
 3. The relocatable securityinspection system of claim 2, further comprising an image processor forconverting the output signal into a visual image of the scanned object.4. The relocatable security inspection system of claim 1, furthercomprising a sensor system that generates information used to modify aprocessing of an output signal.
 5. The relocatable security inspectionsystem of claim 1, wherein, when in a scanning position, the first legsection is substantially perpendicular to the support beam, the secondleg section is substantially perpendicular to the support beam, and theframe is stationary relative to a moving object being scanned.
 6. Therelocatable security inspection system of claim 1, wherein the first legsection and the second leg section each include a base portionconfigured to rest on a surface and maintain the frame in a stationaryposition during imaging of a moving object.
 7. The relocatable securityinspection system of claim 1, further comprising a radiation shieldattached to the frame for preventing radiation produced by the X-raysource from escaping an inspection area.
 8. The relocatable securityinspection system of claim 1, further comprising a detector disposed onat least one of the first leg section and the second leg section.
 9. Therelocatable security inspection system of claim 1, wherein the first legsection comprises a telescoping portion that is adapted to be retractedor extended.
 10. The relocatable security inspection system of claim 9,wherein the second leg section comprises a telescoping portion that isadapted to be retracted or extended.
 11. The relocatable securityinspection system of claim 1, wherein the vehicle further comprises anarm, wherein, in a transport position, said arm is attached to theframe.
 12. The relocatable security inspection system of claim 11,wherein, to deploy said frame in a scanning position, the arm is adaptedto extend outward, causing portions of said frame to move away from eachother and lock into said scanning position.
 13. The relocatable securityinspection system of claim 1, further comprising a strain gaugepositioned on the frame, wherein said strain gauge is adapted to measurestrain and/or stress in the frame and to determine if frame deflectionis occurring.